This invention relates to method of applying particulate material to objects, and more particularly it is concerned with a method of applying a material of particulate form to an object by using a liquid.
The method of applying a material in particulate form by using a liquid has been widely in use in various fields of industry. One example of the method which is used nowadays to apply a flux of particulate form to members of nonferrous metallic material to join them together by brazing will be described by referring to a block diagram shown in FIG. 3. In this method, a flux of particulate form is poured in water (filtered water or water subjected to ion exchange to provide pure water) to cause same to disperse or dissolve in the water (step 1). Then, the dispersion or solution is sprayed onto metallic members by means of a spray-gun (step 2). Excess water is removed by allowing same to drip down or by means of an air blower (step 3), and the metallic members are placed in a strainer to dry same by using a burner (step 4). Thereafter, the metallic members are placed in a brazing furnace to join them together by heating a brazing material that has been applied beforehand to portions of the metallic members at which they are to be joined together.
Some disadvantages are associated with this method of the prior art of applying particulate material to metallic members or components. When excess water is removed, a substantial quantity of flux would be lost together with the removed water when water is allowed to drip down or dried by blowing air thereagainst. Thus the fluxes of particulate form that are used would be lost in large quantities, and, in addition, difficulty would be experienced in distributing the flux uniformly on the surfaces of the metallic components to be joined together by brazing.